CORES: The imaging acquisition and analysis core was established in response to the growing need of several investigators for High-resolution CT image acquisition and analysis across a range of species. Since our publication of the first use of HRCT to assess airway reactivity in dogs, we have published several subsequent studies, using HRCT to measure airway walls and airway size changes in dogs, in sheep, and in humans. Due to developing needs, we have hired Dr. Masaru Ishii to expanding the imaging acquisition and analysis core unit to include Magnetic Resonance imaging, specifically hyperpolarized helium (3He) imaging acquisition and analysis. The strength of the imaging core has been demonstrated by our ability to acquire highly reproducible lung images for quantitative analysis of airways and parenchyma. Conventional pulmonary function measurements are unable to assess airway stiffness or reduced maximum airway size, as measured by changes in airway size with lung inflation. HRCT is a direct, noninvasive, radiological technique that can accurately and reliably measure airway luminal area and airway wall thickness in human airways in vivo. Using HRCT, one can make repeated airway luminal and airway wall thickness measurements of multiple airways at different lung volumes in vivo. In the proposed work, we will use HRCT to make repeated measures of airway size at various lung volumes, airway wall thickness in multiple airways (2nd to 8th generation airways), and lung parenchyma! density in subjects with COPD as an index of airway remodeling. Furthermore, the development of a consistent database of airway images will be instrumental in linking projects related to progression of COPD. HRCT also has been demonstrated to be a precise tool for the quantification of emphysema by measurement of lung parenchyma! density. In order to increase the sensitivity of this measurement of treatment and harmful exposures, we plan to evaluate regions of lung with low destructive index as a measure of COPD progression. The Core will support Projects 2 and 5 and will interact with Core C.